Heat-radiating electromagnetic wave absorber

Abstract

A heat-radiating electromagnetic wave absorber molded in a predetermined form from a mixed composition comprising Fe-Si alloy powder as soft magnetic powder and a thermally conductive filler in an organic matrix. This heat-radiating electromagnetic wave absorber has better thermal conductivity, as well as excellent electromagnetic wave absorbing property in high frequency band.

What is claimed is:  
     
       1. A heat-radiating electromagnetic wave absorber molded from a mixed composition comprising soft magnetic powder and a thermally conductive filler in an organic matrix, wherein the soft magnetic powder includes Fe—Si alloy powder in which the content of silicon is in the range of from 5 to 7 percent by weight. 
     
     
       2. The heat-radiating electromagnetic wave absorber according to  claim 1 , wherein the average particle size of the Fe—Si alloy powder is in the range of from 1 to 50 μm. 
     
     
       3. The heat-radiating electromagnetic wave absorber according to  claim 1 , wherein the content of the soft magnetic powder in the mixed composition is in the range of from 5 to 70 percent by volume. 
     
     
       4. The heat-radiating electromagnetic wave absorber according to  claim 1 , wherein the organic matrix is a silicone gel. 
     
     
       5. The heat-radiating electromagnetic wave absorber according to  claim 1 , wherein the thermally conductive filler is selected from the group consisting of metal oxides, metal nitrides, metal carbonates, metal hydrides, and combinations thereof. 
     
     
       6. The heat-radiating electromagnetic wave absorber according to  claim 1 , wherein the thermally conductive filler is selected from the group consisting of silver, copper, gold, iron, aluminum, magnesium, their alloys, and combinations thereof. 
     
     
       7. The heat-radiating electromagnetic wave absorber according to  claim 1 , wherein the thermal conductivity of said heat-radiating electromagnetic wave absorber is at least 2.0 W/(m·K). 
     
     
       8. The heat-radiating electromagnetic wave absorber according to  claim 1  wherein said heat-radiating electromagnetic wave absorber is in the form of a sheet. 
     
     
       9. The heat-radiating electromagnetic wave absorber according to  claim 8 , wherein the thickness of the sheet is in the range of 0.2 to 5 mm. 
     
     
       10. The heat-radiating electromagnetic wave absorber according to  claim 8 , wherein the sheet has at least one adhesive surface. 
     
     
       11. A mixed composition comprising soft magnetic powder and a thermally conductive filler in an organic matrix, wherein the soft magnetic powder includes Fe—Si alloy powder in which the content of silicon is in the range of from 5 to 7 percent by weight. 
     
     
       12. The mixed composition according to  claim 11 , wherein the average particle size of the Fe—Si alloy powder is in the range of from 1 to 50 μm. 
     
     
       13. The mixed composition according to  claim 11 , wherein the content of the soft magnetic powder in the mixed composition is in the range of from 5 to 70 percent by volume. 
     
     
       14. The mixed composition according to  claim 11 , wherein the organic matrix is a silicone gel. 
     
     
       15. The mixed composition according to  claim 11 , wherein the thermally conductive filler is selected from the group consisting of metal oxides, metal nitrides, metal carbonates, metal hydrides, and combinations thereof. 
     
     
       16. The mixed composition according to  claim 11 , wherein the thermally conductive filler is selected from the group consisting of silver, copper, gold, iron, aluminum, magnesium, their alloys, and combinations thereof. 
     
     
       17. The mixed composition according  claim 11 , wherein the thermal conductivity of said mixed composition is at least 2.0 W/(m·K).